final practice questions

Question 1

Theoretical upper limit for the mass of a star

Answer 1

150-200 solar masses

Question 2

How stars orbit in our galaxy

Answer 2

Disk: orbit in the same direction with little vertical motion
Bulge/halo: random orientations

Question 3

Neutron star limit to create a black hole?

Answer 3

3 Msun

Question 4

Put these eras in order from least to most recent: Planck Era, Era of Atoms, Particle Era, GUT Era

Answer 4

Planck, GUT, Particle, Atoms

Question 5

What is a flaw of the original, pre-inflation Big Bang Theory?

Answer 5

Fails to explain large-scale uniformity of the temperature of the universe

Question 6

What evidence is used to detect potential black holes?

Answer 6

Gravitational waves
Motion of stars and gas nearby
Materials in the surrounding accretion disk fading from view

Question 7

How would a larger Hubble constant affect our understanding of the age of the universe?

Answer 7

The universe would be younger

Question 8

How to measure distance from the center of the Milky Way?

Answer 8

Use RR Lyrae variable stars to measure distance to globular clusters

Question 9

The cause of the first accelerating expansion of the universe

Answer 9

inflation

Question 10

Why are white dwarf supernovae good standard candles?

Answer 10

They have about the same luminosity due to the Chandrasekhar limit

Question 11

Difference between a nova and a supernova

Answer 11

Supernovae leave nothing behind; novae leave a white dwarf behind

Question 12

Where does energy come from in a black hole?

Answer 12

Kinetic energy comes from matter falling into the black hole

Question 13

What do different colors in the Cosmic Microwave Background represent?

Answer 13

Temperature

Question 14

What electron degeneracy pressure?

Answer 14

High electron density, high speed of electron movement

Question 15

What supports white dwarves against the crush of gravity?

Answer 15

Electron degeneracy pressure

Question 16

Major galaxy types

Answer 16

Spiral
Elliptical
Irregular

Question 17

Evidence supporting the Big Bang Theory

Answer 17

The universe is expanding
Correctly predicts the abundance of helium and other light elements
Detected leftover thermal radiation from the Big Bang

Question 18

What percentage of our universe are ordinary matter, dark matter, and dark energy?

Answer 18

4% ordinary matter
22% dark matter
74% dark energy

Question 19

What is the geometry of our universe?

Answer 19

Flat; at critical density

Question 20

What happens to light emitted near the event horizon of a black hole?

Answer 20

It is redshifted and appears to stretch out

Question 21

What likely contributes to formation of elliptical galaxies in densely populated galactic clusters?

Answer 21

Frequent collisions and mergers with other galaxies

Question 22

According to Hubble’s law, galaxies that are farther away are…

Answer 22

moving away faster

Question 23

How do new stars form when galaxies collide?

Answer 23

Clouds of gas and dust combine to create star-making regions

Question 24

Why might distant regions in the CMB appear similar?

Answer 24

They were once close together, but moved apart due to inflation

Question 25

What must a star's mass be to create a Massive Star Supernova?

Answer 25

>8Msun

Question 26

What must a star's mass be to create a White Dwarf Supernova?

Answer 26

1.4Msun

Question 27

What happens to angles on a curved surface?

Answer 27

On a convex surface, an angle will be more than it usually is

Question 28

What color indicates ongoing star formation?

Answer 28

Blue

Question 29

What type of sensors are best for observing earliest galaxies in the universe?

Answer 29

Infrared

Question 30

If total density of matter and energy in the universe were to slightly exceed critical density, what would be the geometry of the universe?

Answer 30

spherical

Question 31

Rank parts of the galaxy from youngest to oldest

Answer 31

Outer arms, middle arms, center, halo

Question 32

Suppose the total density of matter and energy is less than the critical density. What could we conclude about the universe?

Answer 32

Hyperbolic geometry

Question 33

How do elliptical galaxies differ from spiral galaxies in composition?

Answer 33

Less gas and dust than spiral galaxies

Question 34

During what era in the universe's history would you find conditions for fusion of protons and neutrons into helium nuclei

Answer 34

Nucleosynthesis

Question 35

What significant change followed the era of nucleosynthesis?

Answer 35

Formation of neutral atoms as the universe cooled

Question 36

Spiral galaxies' rotation curves can be measured with...

Answer 36

The doppler shift of the 21cm line of atomic hydrogen

Question 37

Cosmological Principle

Answer 37

The universe looks relatively the same no matter where you are in it

Question 38

Which force is present in the GUT era of the universe?

Answer 38

gravity

Question 39

What is the Hubble Tension

Answer 39

tension between seemingly incompatible measurements of the rate of expansion of the universe

Question 40

What will eventually happen to a main sequence star with a mass similar to our sun's?

Answer 40

It will become a red giant, then a planetary nebula, then a white dwarf

Question 41

Why can't dark matter be made of protons, neutrons, or electrons?

Answer 41

Protons, neutrons, and electrons affect and interact with photons

Question 42

How to measure amount of dark matter in an elliptical galaxy?

Answer 42

measure speeds of different stars at different radii from the center of the galaxy, and determine how much mass is inferior to the orbit

Question 43

Order these objects from most to least luminous: galaxy, supernova, brown dwarf, quasar, white dwarf, pulsar

Answer 43

Quasar, supernova, galaxy with 100 million stars, pulsar, white dwarf, brown dwarf

Question 44

What is WIMP?

Answer 44

Weakly Interacting Massive Particle; a potential explanation for dark matter

Question 45

What can cepheid variable stars be used for?

Answer 45

Their periods can be used to determine luminosity